Equivalent & Substitute Parts for 3KP8.5CA-B

Part Overview

The 3KP8.5CA-B is a Transient Voltage Suppressor (TVS) diode manufactured by Littelfuse Inc., designed for general-purpose voltage clamping applications. This bidirectional Zener diode features an 8.5V reverse standoff voltage and 14.4V maximum clamping voltage, with a peak pulse current rating of 208.3A and 3000W peak pulse power dissipation. The device is housed in a P600 axial through-hole package and operates across a temperature range of -55°C to 175°C.

The 3KP8.5CA-B is currently classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production or repair requirements for systems utilizing this component.

Substiute Parts

3KP8.5CA-B

Littelfuse Inc.In Stock: 11463KP8.5CA-B Datasheet

Current PartRFQ

5KP8.5CA-B

Littelfuse Inc.In Stock: 8405KP8.5CA-B Datasheet

DirectRFQ

3KP8.5CA-TP

Micro Commercial CoIn Stock: 7043KP8.5CA-TP Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for TVS diodes is determined by strict equivalence across electrical and mechanical parameters. The following criteria establish valid substitution relationships for the 3KP8.5CA-B:

Electrical Equivalence Requirements:

• Voltage - Reverse Standoff (Typ): 8.5V
• Voltage - Breakdown (Min): 9.44V
• Voltage - Clamping (Max) @ Ipp: 14.4V
• Operating Temperature Range: -55°C to 175°C (TJ)
• Bidirectional Channels: 1
• Type: Zener

Mechanical Compatibility Requirements:

• Mounting Type: Through Hole
• Package / Case: Axial configuration

Identified Substitute Parts:

1. 5KP8.5CA-B (Littelfuse Inc.) – Meets all electrical parameters with identical voltage specifications and temperature range. Differs in peak pulse current (354.2A vs. 208.3A) and power dissipation (5000W vs. 3000W), representing a higher-rated variant within the same electrical class. Through-hole P600 axial package maintains mechanical compatibility. Product status: Active.

2. 3KP8.5CA-TP (Micro Commercial Co) – Meets all electrical parameters with identical voltage specifications, peak pulse current (208.3A), and power dissipation (3000W). Package variant uses R-6 axial configuration instead of P600, maintaining through-hole mounting compatibility. Product status: Active.

Parameter Comparison

Engineering Selection Recommendations

5KP8.5CA-B Selection Criteria: The 5KP8.5CA-B is an active product from Littelfuse Inc. with identical electrical specifications to the 3KP8.5CA-B. This substitute provides higher peak pulse current (354.2A) and power dissipation (5000W) ratings, making it suitable for applications requiring enhanced transient protection margin. The P600 axial package maintains direct mechanical compatibility with existing PCB layouts. ROHS3 compliance and active product status ensure long-term supply chain availability and regulatory alignment.

3KP8.5CA-TP Selection Criteria: The 3KP8.5CA-TP is an active product from Micro Commercial Co with identical electrical and power specifications to the 3KP8.5CA-B. This substitute uses an R-6 axial package instead of P600, requiring PCB layout verification for lead spacing and mounting hole compatibility. The device maintains through-hole mounting and meets ROHS3 compliance requirements. This option is appropriate when package footprint differences are accommodated in the design.

Compliance Considerations: Both substitute parts maintain ROHS3 compliance and operate within the same temperature range as the original component. Selection should prioritize active product status and supply chain availability for long-term production support.

Frequently Asked Questions (FAQ)

Q: Can the 5KP8.5CA-B directly replace the 3KP8.5CA-B in all applications?

A: Yes, from an electrical standpoint. The 5KP8.5CA-B meets all voltage and temperature specifications of the 3KP8.5CA-B. The higher peak pulse current (354.2A vs. 208.3A) and power dissipation (5000W vs. 3000W) represent increased capability, not incompatibility. The P600 axial package is mechanically identical, requiring no PCB layout changes.

Q: What is the difference between the P600 and R-6 packages used in the substitute parts?

A: Both P600 and R-6 are axial through-hole packages for diodes. The primary difference is lead spacing and physical dimensions. The 3KP8.5CA-TP uses R-6 packaging, which may have different lead pitch than the P600 package. PCB layout verification is required to confirm mounting hole compatibility before substitution.

Q: Why does the 5KP8.5CA-B have higher current and power ratings than the 3KP8.5CA-B?

A: The 5KP series represents a higher power variant within the same voltage class. Both devices maintain identical voltage clamping characteristics (8.5V standoff, 14.4V clamp), but the 5KP variant is designed to dissipate greater transient energy. This makes it suitable for applications with more severe transient conditions.

Q: Are both substitute parts suitable for new designs?

A: Both 5KP8.5CA-B and 3KP8.5CA-TP are active products with current manufacturing status. Either is appropriate for new designs. The 5KP8.5CA-B from Littelfuse Inc. offers the advantage of identical packaging to the original component. The 3KP8.5CA-TP from Micro Commercial Co provides electrical equivalence with package variation.

Q: What compliance certifications apply to these substitute parts?

A: All three parts (original and substitutes) are ROHS3 compliant. The 5KP8.5CA-B and 3KP8.5CA-TP are classified as REACH Unaffected, confirming regulatory alignment for international applications.